1. Field of the Invention
The present invention relates to a spin injection magnetization reversal type magnetic random access memory and a manufacturing method thereof.
2. Description of the Related Art
A spin injection magnetization reversal type magnetic random access memory (MRAM) attracts attention as a memory in which information can be written with a low current, and an application as a high-speed RAM enabling high-speed reversal is expected.
When performing an operation at a high speed, a cell to which a voltage is applied must have a minimum bit number to suppress a loss of a charge/discharge time in reading and writing operations. Thus, a source line and a bit line are provided as wiring lines through which a writing current is flowed, and these lines are arranged in the same direction. As a result, the cell to which a voltage is applied becomes minimum, thereby enabling the high-speed operation.
Further, when the number of cells to which a voltage is applied is increased, a leak current is also increased, which leads to a problem of a reduction in a reading signal ratio. Thus, 1MTJ+1Tr must be arranged between the source line and the bit line.
However, when using a planar transistor, a contact which connects a source diffusion layer with the source line and a contact which connects a drain diffusion layer with the bit line must be arranged in a staggered pattern to prevent the source line and the bit line extended in the same direction from being short-circuited. Therefore, there is a problem of an increase in a cell area.
It is to be noted that information of conventional technology documents concerning the present invention is as follows.    [Patent Document 1] JP-A 2004-179489 (KOKAI)    [Patent Document 2] JP-A 2002-208682 (KOKAI)